wilkeeson



2l sheets-sheen `1. B. Ml WILKERSON.

'DENTAL CHAIR.

310,413,156. f Patented 0 et. 15, w89.

Inl/6702222?.-

BASIL lli. ILKERSON, OF BALTIMORE, MARYLAND, ASSIGNOR, BY SIESNEASSIGNMENTS, TO THE S. S. lWHITE DENTAL MANUFACTURING tthih 'PAN"Y,til llLADELPHiA, PETSNSYLVANIA.4

near/fu. CHAIR.

SLPECFIGTION forming part oiaihetters Patent No. 413,156, dated October15, V Application led March 14, 1879. (No model.) y

To @ZZ wwnfi'i'in/ty concern,.- J

Be it known that I, BAsIL M. WILKERSON,

of Baltimore, in the State of Maryland, havev invented certain neur anduseful Improvements in Dentists Chairs, of which the following is aspecification.

This invention relates to improvements applicable to that class ofchairs the frames or bodies oit which are capable of being adj ustedvertically and revolved horizontally about supporting pedestals orbases; and my improvements consist in certain organizations of parts andnovel combinations et devices, as hereinafter fully set forth.

In my Letters Patent hie/197,441, dated November 20, 1877, I. have shownand described a dentists chair of this class, in which a vertically-movable support for the chai r frame or body and a mechanical lift forele 7ating the same are combined with means distinct fromand,indepei'nlent oi? the elevating meehanism, and which have no liftingfunction, but simply serve to uphold said supportant any point to whichit is raised hy the elevating,l mechanism and to permit it, whendesired, to pass gradually and without shock from that elevated point toalovverone. Under thai ar! rangement, however, the same instrumenial'ity through the medium of which the cho-irframe support was upheld wasalso the agent VVby Whose yielding` resistance under certain ltardefhwith a view to causing its descent to conditions the tall of theseat-snpport was rcbe gradual and easy. ln my present chair l retain-asfar as possible the same conditions of movement, so as elevating andlowern ing,` are conenned, as in my said patented 4specificationwhenever l use the term retarding mechanism I intend the instrumen*tality or combination of elements Whicliects body itself and attachments.

simply to oder yielding resistance to the downward movement of thechair-frame and not to either elevate or uphold and lock in posi lcionthe said frame.

The retarding or lowering mechanism which, in illustration ofmyinvention', I have herein shown comprises a plunger (which may ormayvnot be the Vplunger or support that ear rires the chair frame orbody) adapted tewerk in a. cylinder or'shell containing a liquid, suolias oil. There need be no tight vfitting between the plunger and ease inwhich it Works, the intention being to permit the plunger te 'descendwhen the chairsupport is u.n'

locked audio displace the liquid in the case, the rate of displacementgoverning the speed of descent. ln other lwords, the body of liquidunder the plunger is never entirely ooniined, thus permitting,` thedescending plunger to move without encountering other than a yieldingresistance due tothe displacement of the liquid. l have also devisedother improveniente directed to the locking or upholding mechanism, tothe lifting mechanism, to the manner of connect ing,r the chair-body'ivith its support, und to the structure ot the chair These can best beexplained and understood by reference to the accoinpanyinf.,v drawings,in which Figure l is a perspective view of one form of chair embodying'my invention, only so much of the 'chair being represented as needed inorder to illustrate my improvements. Fig. 2 is a view, on an enlargedscale, partly in rvertical central lsection and partly in elevation.Fig. 3 is a perspective view oi the rotary cylinder which carries theseat-support and its adjunctsA section, on an enlarged scale, of thelower end or head of the retarding-plunger. Figs; 5 `to 9, inclusive,represent a modified arranged ment of parts, to be hereinafter 4referredto. Fig.. l0 is a plan view of the supportingbracket of-the upholding orlocking mechanism, showing the guide-plate of said bracket for thechaiiframe support orplunger.

Referring; new to Figs'. 1 to 4f, A is the nonrotating pedestal or basesustaining the ro- `tary cylinder or main support B, which ear- Fig. lis a vertical central ries the vertically-adjustable chair-framesupport, &c'., and is locked lin position by means Iside in contact withthe Wall of the cylinder,

and by being embraced on the other sides by the upholding or clampingmechanism, and

i -by guides Afixed to the cylinder and in contact with the respectivelyadjoining faces of the support. This arrange'ment is shown plainly inFigs. 1, ,2, and '3, cii being a guide-plate, against which the supportis pressed by an adjustable upholding-block e on theoppositeg side, andf being a bracket secured to the cyl inder B and provided with aninwardly-eX- tending portion, forming a guide-plate opposite'that sideor face of the seat-support whose edges ay are in contact with the Wallof the cylinder. In these figures, in order to show more clearly theupholding or locking mechanism and also the retarding mechanism, I haveomitted the elevating mechanism uwhich acts upon the chair-framesupport. Itwillbe `understood that elevating mechanism such as describedin my aforesaid Letters Patent, or other suitable elevating mechanism--such, for instance, as that hereinafter describedcan be used. i

The upholding orlocking mechanism, which ,Y kin the present instance isused to lock the frame-support in any positionyertically that Imay bedesired, is automatic to the extent i that it permits the support to beraised freely;

but it loc-ks it firmly against descent, and must be operated by somepositive means in order to releasethe support and permit it to descendand bring the retarding mechanism into action.

The locking mechanism consists of a block e, whose plane face is heldagainst the correspending face or side of the support (l by means of arod g, provided at one end (sce Figs.1,3,`9,and l0) with a roundedextremity that seats itself in a like socket or depression in the blockand at the other end with a concavity or socket which is entered by theend of. a screw 7i, which screws through a .bearinglug t' ofthe bracketf, attached to the cylindery B. The rod g is slightly inclined, having`itsend which engages the block e a little higher than the other end',which engages the screw. This arrangement, so far as the parts le g hare concerned, is most plainly shown in section in Fig. 9. Under thisarrangement it will be seen that the upholding or locking` mechanismwill readily and automatically yield toupward passage of the support (lbut the moment the elevating mechanism ceases to act and the support Ctends to descend, this will have thev effect of tending to straightenout andbring into line the kneejointed parts g 7i, with the result offorcing the clamp-block e tightly against the support, which will thusbe firmly locked between the block. e on the one side and the plate d onthe other; and the greater the do iWa-rd pressure on the seat-supportthe tighter will it be locked. The screw h is used to regulate theadjustment of'theparts of the knee-jointed support.,v 'The block c iscapable of slight vertical movement in a guideway at j in the bracketf,and is pressed down (so as to keep the parts in proper position) bymeans of a spring 7c. A lever D, pivoted to the cylinder B and workingtherethrough against the underside of the block, as indicated in Fig. 3,serves to lift the block against the stress of the spring' whenever itis desiredy to unlock and release the support C. This lever, it will beseen, is supplemental to and independent of the locking or clampingdevices in so far as their clamping action is concerned, the leverserving simply to trip the clamping devices to permit of the descent ofthe support.

In the modification of the locking or holding mechanism shown in Fig. 9,and also in perspective in Fig. 5 and in plan in Fig. 7, the lever ortreadle D is provided with a pin Z, which extends through a slot Z in aboxlike housing B', fixed to the top' of the cylinder B, and engages theblock e. l The block is raised to release the seat-support by means ofthe lever acting again-st the stress of a spring 7n', which exertsdownward force on the short end of the lever and serves to depress' thatend when pressure by the hand or foot is removed from the opposite endof the lever.

A convenient form of lifting mechanism is shown in Figs. 5, (i, 7, andS. It has the general characteristics of the mechanism for the samepurpose described in my aforesaid Letters Patent, in that it is alifting mechanism operated by a treadle or foot-lever E, catoliingholdafter hold and raising the chair step by step. It, however, differs indetails from the patented mechanism. 'lhelever E,which is operated bydownward pressure upon its outer end to effect the raising of theseat-sup port by a step-by-step movement, is pivoted or has its fulcrumin the housing or box B.

is entered by a pin n', projecting laterally from a cam fn., pivoted toone en'd of a bar o, which is provided at its opposite end with a Hangeor hook o and forms one jaw of a clamp for engaging the support C. Onthe clainp-bar o is mounted the slide-block p, which acted on by the camn and constitutes the other jaw of the clamp. This arrangement is shownplainly in Fig. 8, which is a perspective view of' the clamp and ap'ortion of its actuating-lever. The clamp-jaws are adapted to enga-gethe support C, as shown IOO IIO

' lts inner end is provided with a slot m,which in Fig. 7. When thelever E is depressed it lock the support in the clampbodily, and with itthe seat-support which it grasps. The pressure of the foot is now'released 'from `the, lever and the latter,

through the instrumentality of a spring shownv inffFig. as secured tothe housing B and .acting 'on the lever, is returned to its normal.andltoj .lift it another step, when the pedal end of the foot-lever isagain depressed and .the elevating' operation continued to the ex tentdesired: While the lifting devices release Athe support and retnrnwtoposition to Ctake a fresh hold' the upholding or locking mechanismbefore described acts to securely position to which it has already beenlifted.

' The mechanisms thus far described answer `admirably the purposes forwhich they are intended; but it Will be seen that were the plunger orchair-body support left entirely l free Vto descend when it is unlockedits descent 'would be sudden' and violent. Therc-l fore means areprovided to render that descent gradual and easy.. To effect this is thevoiice of the herei nbefore-inentioned retarding mechanism, one form ofwhich I now proceed to describe.

In Figs. l to e the retarding mechanism comprises an auxiliary plungervF, which moves with the Achair-support C and is connected therewithandiits in acylinder or well G, fixed to and arranged in the rotarycylinder B. rlhe cylinder Gis closed at the bottoin and is intended tocontain oil or other liquid; The plunger is notrequired to lit itscylinder accurately'and no packing between the two is needed. Theplunger may be closed atthe head or bottom, in which event the onlyescape for the liquid before the deseen d- Ving plunger is by leakagepast or by the l plunger-head into the space which exists be- 4foratcddiaphragme s s.

tween the plunger and the'walls of its cylin der; or various other ways,which will readily suggest themselves, may be employed to provide forgradual displacement of the-liquid as the plunger descends. A convenientarrangement for the purpose consists in 1naking the auxiliary plungerhollow andinproviding `its lower end with a valve vll', which hasaislight play between two centrally-per- Wh'en the valve drops, as shownin lfig. Al, its spaced bottom lugs or feet fWhold it up from the lowerdiaphragm and liquid is free to pass by way of the spaces between thefeet from one side of the valve to the other through the centralopenings in the diaphragms.. This is the po sition occupied by the valveger rises, thepassageway formed bythe opendoin.

ings between the valve-feet being of suiii- Vciently largev area topermit liquidto pass the valve with entire freefrom above below 4 When,on the other hand, the valve is closed againstthe upper diaphragm,nomliqlcarried by the chair.

when the plunuid can pass through it from when, as is the case here, thevalve is provided itself with a' small `central opening, which, asshown, is covered by. a partiallyclosing smaller valve t. This openingneed. not be covered at all butthe valvetis added, to showhow the o)ening whichit covers may be graduated iu accordance with the weight Thesupplementalvalve which opens downward, normally stands-fully open,` butis made of spring metal, or is acted on by a spring, torendei itself-adjusting, so kthat in case of the, chair carrying more weight thanordinarily, as when it is occupied'by aheavy person, the pressureinduced'by the Weight will have the eiect of partly closing the valve,and so reduoing'the size ofV the opening. Inthis way the rate ofmovement in descent can be made even and below, save 1 uniform, nomatter what may be the weight of the person occupying ever the lockingmechanism is released, the plungermoves down. through the liquid, thelatter oozing through the small central valve opening and also upoutside of the plunger between it and the wall of the cylinder, andgathering in the upper parts of the cylinder and the hollow plunger. lis provided in the top oi the plunger for escape of confined air. p

I make the head or lower end ot the plunger of greater diameter thantheplungenbody, and forni above this enlarged end one or openings n inthe end of the liquid lnaypass freely in and out of the plunger. I thusprovide a mechanism which, While it does not act to lock. or sustain thesupport in an elevated position, and does not consequently require thatnice and accurate fitting a nd delicate adjust in cnt which it wouldrequire were it used for that purpose, yet acts to retard the fall ofthc chair-frame support when thc latter is released from the lockingmechanism, and to malte its descent gradual and easy. l

ln lieu of employing an vauxiliary plunger, i can make the main plungeror chair-franixe support C answer thc two purposes of support theplunger, so that the chair.` Whenr A small rent-hole J more Ioo

.IlO

ing the chair and rctarding itsdescent. Such 4 an arrangement is shownin Figs. 5 to19. -Thc rotary cylinder B inthis instance is closed at thebottom, so as to contain ccivcs the hollow plunger C, at the bottoniwith a valve arrangement resembling that on the auxiliary plunger andsimilarly lettered.

box B', fixed on top liquid, and reof the cylinder Aandcontainingvworking parts of thelifting and lockn ing mechanism, willreceive, if need be, such` of thedisplaced liquid` as can notbri-contained in the cylinder or' plunger. The operation of thisretardin'g mechanism is whole, prefer this last arrangementgas it is.

which is provided 'lhe housing` or vcovered similar to that which hasalready been described.- 1I, on the simpler and `enables me t dispensewith anv Y.auxiliary plunger.

In 9d have represented the .upper-'bean ings of the seat-supportingplunger as consisting of 'two friction-rollers w i0, mounted somellittle distance apart from one another in the box B'. The block e, onthe other side of the plunger, is arranged opposite the space betweenthe 'roller-bearings, and in this way the plunger may be clamped verytightly, at

l the same time that it is in condition to move freely and withoutfriction when the clampblock e is tripped. The upper bearings for theplunger are so located that when the plunger is at its lowest positionthey are very near its top, the'object being to obtain a vertical rangeof movement as extended' as possible.

The chairframe or body proper H is fixed to or forms part of a plate II,pivoted atj to the side of the plunger or vertically-adjust able supportC. The chair-frame which is and forth on the point m as an axis.- Inorder to secure the chair-frame at any desired angle of inclination,Imake use of means which automatically clamp it, comprising a set-l screwor clam ping-screw y, which screws into the support C and passes looselythrough a curved slot .e in the plate H.v Thescrew is provided with abearing-Hange y', which rests against the chair-frame plate. By turningthe screw in one direction its clamping face or ange y will be drawnagainst the plate and so will clamp the latter against the scat-Isupport. When the screw is turned in the other direction, its pressurewill be relaxed and the chair-frame will be free to tilt. In order tobetter insure clamping action,I form on the-support C two raisedbearings y2 y2, The clamping-face o f the screw is on the side of theplate opposite that next these bearings and in a position intermediatebetween said bearings, so that when it.iS screwed up the plate will beheld between the points @fig/2 'and 'y'. On the outer end of the screw yis fixed a lever I, and a spring J, of proper strength and suitablyarranged, is provided, which acts on the lever to move it in thedirection required to cause the screw to exercise clamping-pressure.That pressure, whenever it is desired to change the angle of in- 5oclination of ,the chair, is relieved by turning A the lever against thestress of the spring.

The moment the lever is released the springl A6o cally movable, and isprovided with aclamp- `ing or locking device M, which constitutes also ahandle by which said back may also be `raised. The back L, however, notonly is vertically adj ustable,but can tilt laterally on theclamping-screw M as an axis. This screw passes into`the' chair-backthrough a vertical thus carried bythe support C can tilt back\ slot inthe supportihg-standard N of the chair-4 "j r frame. v

I find it advantageous tomake one-or both arms of the chairadjustabledaterally, and. also vertically as Well.` I also find it ofadvantage, in order to furnisha lseat or support vided with a horizontalpart P', extending' under the chair and, 'longitudinally slotted,

as at 3. From the chairframe extends a` l vertically-slotted plate R, towhich the part P is attached by a s`et-screw 4, that passes through theslots' at their intersectiomand is provided with a handle 5, by which itmay .be loosened or tightened. The slotted barP permits the chair armand stem to be moved bodily to and from the chair-seat. The slottedsupporting-plate R permits the arm to be vertically adjusted, and theset-screw4serves as a pivot on which the arm and its support` ing-stemcan move as an axis. The-arm under this arrangement can be iutned down,so as to be secured in a positionvwhere it may serve as a seat or rest'for the operator. This pivoted arrangement can b e used 'to advan tage,whether one or both of the parts P R .y

be slotted, or, indeed;vl if the slotted connection be disp'eiiscdmithand the parts have simply a pivotal connection. have one or both of itsarms made adjustable in this way.

I have described the manner yin which prefer to carry my improvementsinto effect.

.100" The chair may It will be understood, however, that the details ofconstruction may be varied to a con siderable extent withoutdeparturefrom the invention. I do not limit myself, therefore, to theparticular details herein described in illustration of my invention;lbpt lWha-t I claim, and desire to secure by Let-- ters Patent, isy Yl."l`he combination, substantially as set forth, of a liquid-carryingcylinder,-a plnger movable up and down in the liquid in the cylinder,the plunger-head by which the liquid above and below it communicates atall times, and `the chair-frame .connected with the plunger andpartaking of its movements, whereby the descent of the chair-f1ane,whenthe plunger is free to move downward, may

automatically be retarded by gradual displacement of the liquid beneaththe'plungerhead and its passage upward.

2. The combination, substantially as set forth, of a liquid-carryingcylinder, a hollow plunger movable up and' down in the cylinder, theplunger-head, an automatically-.acte ing valve seated in thepln`nger-head and by which communication is at, all times mairnl`.tained between liquid above and below said elaine- 5 head, and thechair-frame connected with and partaking ot' the movements of theplunger, whereby descent of th e ehair-fran1e,when the plunger is freeto move downward, may automatically be retarded by gradual displacementof the liquid beneath the plungerhead and its passage upward.

3. The combination,` substantially as set forth, of a liquid-carryingcylinder, a hollow plunger movable up and down in the liquid in thecylinder, the plunger-head by which the liquid above and below it in thecylinder communicates at all times, an automaticallyaeting valve seatedin the plunger-head and ,by which communication is at all timesmaintained between liquid in the plunger and in the cylinder, and thechair-frame connected with and pai-taking of the movements of theplunger, whereby the descentl ol' the chairf1"z1n1e,when the plunger isallowed downward movement, may automatically be retarded by gradualdisplacement of the liquid beneath, the plunger-head and its passageupward around and into the plunger.

4. 'lhc combination of the liquid-carrying cylinder, a hollow plungermovable up and down in the cylinder, the chair-frame connected with andpartaking of themovcments of the plunger, the plunger-bead, anautomatically-acting main valve seated in the plunger-head, and by whichcommunication is at all times maintained between liquid above and belowsaid head, andthe automatically-acting supplemental valve for varyingthe area of the communicating way or passage alforded by the main valve,substantially as and for the purpose set forth.

The combination of a liquid-carrying cylinder, a chair-frame support orplunger movable up and down in 'the cylinder, having bearings at theupper end thereof and lit-ting loosely at its lower end or headthereinbelow said bearings to allow of constant communication between theliquid above and below said head, the lifting devices, and the lookingor upholding devices, substantiallyas and for the purpose set forth.

G. The combination of the pedestal or base,

the chair-frame support or plunger carriedv thereby, the liftingdevices, the automatic clamping devices sustained by connection with thepedestal or base, consisting of the clamp-block and the self-adjustingkneejointed support therefor, said clamping devices yielding to allowthe chair-frame support or plunger to ascend but preventing its descent,and the lever for tripping` the clamping devices to release saidplunger, substantially set forth,

7. The combination, substantially set forth, of the chair-frame supportor plunger, the clamp-bar provided with the end ilange for engaging theplunger at one side, t-he slideblock for engaging the plunger at theopposite side, the lever, and the cam by which the .lever is connectedwith the clamp-bar and slide-block, whereby the clamp-bar flan ge andvslide-block may be caused to grip theplunger for elevating it.

8. The combination, substantially as set forth, of the pedestal or base,the verticallyadjustable support or plunger carried thereby, theclamp-block acting on said plunger, and the adjustable thrus ing'jointedsupport of said block, said supp'o'rt yielding to allow upward movementof the plunger.

E). The etnnbination, substantially as set forth, of thepedestal orbase, the verticallyadjustable plunger carried thereby, the clam pblockacting on said plunger, the self-adjusting thrusting-support for theclamp-block, said support yielding to allow upward movement of theplunger and acting on said block to automatically loelr the plungerlagainst d'escent, and thelever actin g on the clamp-block to release theplunger.

lO. The combination ot the seat, the arm, the supporting standard orstem of the arm, and the pivot extending parallel, ornearly so, withsaid arm, and passing through said stem to connect it with the seat,whereby the arm may be swung in a plane transverse to the seat andadjusted toward and `from it, substantially as and for the purpose setforth.

ll. The combination of the vertically and centrally slottedehair-frame-baek standard, the vertically-adjustable andlaterally-tilting chair-back, and the screw-clamp secured to andcarrying or moving 'up and down with the chair-back, and engaging withand movable inthe slot of said standard, whereby the chair-back may bemoved up and down by ,and swung about said clamp, substantially as andfor the purpose set forth.

In testimony whereof I have hereunto signed myname in the presence of`two subscribing witnesses.

BASIL M. VILKERSOF.

Witnesses: l

Roer. W. SMITH, Jr.,

J. W. SELBY.

lOO

